AI agents use metadata_user_upsert to create or update resources in Remnawave — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Remnawave environment.
This tool modifies user metadata, which is reversible through subsequent updates or deletions. It does not permanently destroy data (not Destructive), execute arbitrary code (not Execute), or handle financial transactions (not Financial).
From the tool's definition Tool name 'upsert' and description 'Create or update metadata for a user' indicate reversible modification of user data. The upsert pattern (insert-or-update) is a standard Write operation.
Documented attack patterns abuse exactly the kind of access metadata_user_upsert gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Remnawave, and nothing reaches the server without passing your rules. This is the rule we recommend for metadata_user_upsert:
{
"version": "1",
"default": "deny",
"tools": {
"metadata_user_upsert": {
"limits": [
{
"counter": "metadata_user_upsert_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}metadata_user_upsert stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
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Create or update metadata for a user. It is categorised as a Write tool in the Remnawave MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Remnawave MCP server in PolicyLayer and add a rule for metadata_user_upsert: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Remnawave. Nothing to install.
metadata_user_upsert is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the metadata_user_upsert rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for metadata_user_upsert. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
metadata_user_upsert is provided by the Remnawave MCP server (trackline/mcp-remnawave). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 153 Remnawave tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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153 Remnawave tools catalogued and risk-classified — across an index of 42,500+ MCP servers.